[Problem] To provide a hemostatic instrument which can excellently maintain strength of an expanding unit, and which, without operation by a doctor or nurse, can reduce, over time, the pressing force acting on the site where blood is to be stopped to a degree at which vascular occlusion can be prevented. [Solution] This hemostatic instrument 10 is provided with a strap 20 to be wrapped around the wrist W, a fixing means 30 for fixing the strap in a state wrapped around the wrist, and an expanding unit 40 which is linked to the strap and expands with injection of a gas. The expanding unit comprises a resin layer 51 formed from a resin material, a microparticle part 52 which is dispersed inside of the resin layer, and a space part 53 which is formed in the periphery of the microparticle part. The space part contains a gas dispersed inside the resin layer so as not to allow communication between the inner surface and the outer surface of the resin layer.